Top 13 Essential Facts You Should Know About Sea Turtles

There are currently seven species of sea turtles found around the world, each with its own fascinating story behind its name:

• The Loggerhead (also known as the 'Big Head' or 'Longgerhead') gets its name from its notably large head.
• The Hawksbill turtle has a narrow head and large beak-like mouth, resembling a hawk, hence its name.
• The Leatherback is the only sea turtle species without a hard shell. Its name comes from its leathery, flexible skin instead of a traditional shell. It is also the largest sea turtle in the world.
• The Olive Ridley turtle has a light olive-green shell, giving it its distinctive name.
• The Green Turtle is named for the greenish tint of its fat beneath the shell.
• The Flatback turtle is named after its characteristic flat shell.
• Kemp's Ridley turtle is named after Richard Kemp, who first discovered and studied this species.

All seven species are listed in the International Red Book and are protected by global conservation laws, with hunting and trade prohibited in most countries.

Sea turtles are often referred to as the 'messengers of the ocean,' each species playing a unique role in the marine ecosystem. For instance:

• Green Turtles help maintain seagrass bed ecosystems by creating feeding trails that promote nutrient exchange, reduce algae growth, and limit the population of invertebrates.
• Hawksbill turtles have strong jaws that allow them to bite and break apart sponges in coral reefs, creating space for coral larvae to settle and supporting the structural stability of coral reefs.
• Leatherbacks are vital to the marine food chain by controlling jellyfish populations. Their diet mainly consists of jellyfish, and they can digest even the toxins found in jellyfish. By consuming large quantities of jellyfish, they help prevent jellyfish overpopulation, which would otherwise negatively affect fish populations.

In Vietnam’s coastal waters, five of the seven sea turtle species can be found. These include the Green, Hawksbill, Leatherback, and Olive Ridley, all of which have nested in Vietnam's waters. However, the Loggerhead only forages here and does not breed.

Adult sea turtles have few natural predators, but large sharks, like the tiger shark, are known to hunt them. Orcas, or killer whales, have also been reported as sea turtle predators. Hatchlings, however, face a much higher risk of predation and are preyed upon by fish, dogs, raccoons, seabirds, and crabs, with over 90% of sea turtle hatchlings falling victim to predators.

Sea turtles inhabit warm and temperate waters across the globe and often undertake long migrations, sometimes traveling up to 1,400 miles between their nesting and feeding areas. Similar to salmon, sea turtles return to their birthplace to lay their eggs. While their diet varies across species, common foods include jellyfish, crabs, seaweed, snails, and other marine invertebrates.

One of the biggest challenges sea turtles face is human expansion. Waste, such as plastic bags, can be mistaken for jellyfish and pose significant harm or even death if ingested. If a sea turtle's nesting site is disrupted by debris or human activity, female turtles may abandon the site and return to the ocean without nesting. Illegal poaching, boat collisions, and commercial fishing also present threats to sea turtles. Additionally, natural disasters like storms can also impact nesting sites.

Despite being aquatic animals, sea turtles breathe air just like whales. They must surface to inhale oxygen, and their lungs are specially adapted to store large amounts of air, allowing them to remain underwater for extended periods. In fact, when at rest, sea turtles can stay submerged for up to 7 hours without needing to surface for air.

Although sea turtles spend most of their lives in the ocean, they can only breathe on land. This means they need to regularly rise to the surface to fill their lungs with air.

Humans take breathing for granted, as we inhale unconsciously. Similarly, sea turtles swallow water along with their food, a necessary process for them since they don’t produce saliva. Swallowing water with their meals helps them digest properly.

Interestingly, a sea turtle’s esophagus has a special reflex to constrict once food enters, preventing too much water from entering the digestive system, allowing only the food and a small amount of water to pass through. Additionally, sea turtles have a unique mechanism for expelling excess salt from their bodies by secreting salty tears.

A turtle's shell is a complex, protective structure that shields both the back and belly, encasing all vital organs and, in some species, even the head. It is made from the fusion of vertebrae, ribs, and pelvic bones, covered by a tough, leathery skin. The turtle's shell is regarded as an extraordinary product of evolution and is the signature feature of the species.

Out of the seven sea turtle species, six possess hard, protective shells. The Leatherback, however, stands apart with a more flexible, skin-like structure. The Leatherback is also the largest sea turtle, reaching up to 680 kg and 1.6 meters in length.

As the largest sea turtle and the fourth largest reptile after crocodiles, the Leatherback is the sole remaining species of the genus Dermochelys. It is easily distinguishable from other sea turtles because it lacks a hard shell. Instead, its back is covered with smooth, leathery skin. Dermochelys coriacea is the only species in the Dermochelyidae family. The Leatherback is toothless but has sharp ridges on the edge of its upper jaw and backward-facing spines in its throat that help it swallow food. It is capable of diving to depths of up to 1,200 meters and holds the title of the fastest swimming reptile, recorded by the Guinness World Records in 1992 at speeds of 35.28 km/h (21.92 mph or 9.8 m/s) underwater.

Once sea turtles reach maturity, they embark on long migrations back to the very shores where they were born to lay their eggs. These journeys can span thousands of kilometers and take months to complete. During migration, they continue to feed during the day and rest at night on coral reefs and rocky outcrops.

After mating, the male immediately returns to its feeding grounds, while the female stays in the nesting area for up to two months to lay her eggs before returning to her home waters. The Green Sea Turtle, for example, can maintain a swimming pace of up to 44 km per day, covering a staggering 3,410 km from Gielop (Micronesia) to Majuro (Marshall Islands).

Sea turtles are known for their incredible migration distances, with some traveling thousands of miles over the course of their lives. One female turtle swam over 12,000 miles round-trip across the Pacific Ocean, from Papua in Indonesia to the northwest coast of the United States. Both males and females undertake these long migrations between their feeding areas and nesting sites.

Sea turtles play a vital role in maintaining the health of marine ecosystems and coastal environments. In the oceans, particularly the Green Sea Turtle, they are among the few herbivores that graze on seagrass beds, which are essential habitats for various marine species. Overgrown seagrass can negatively affect marine life, and when these beds are destroyed, it creates a chain reaction, impacting countless marine species and, ultimately, humans who depend on these ecosystems.

On beaches, sea turtles contribute to the stability of sand dunes and coastal vegetation. When they lay their eggs, they deposit a significant amount of ocean plants, along with nutrients that help fertilize the dune vegetation as the hatchlings emerge. Each year, sea turtles lay millions of eggs across coastal beaches.

Beyond their ecological importance, sea turtles have been historically valued by humans as a food source rich in protein. Their shells and scutes are used in making jewelry and household items. For fishing communities, sea turtles help sustain healthy seagrass ecosystems, which, in turn, support diverse marine life such as crabs, mollusks, fish, and crustaceans. Many regions, recognizing the value of sea turtles, have implemented permanent conservation efforts that not only protect the turtles but also encourage sustainable tourism, boosting local economies.

All seven species of sea turtles are listed as threatened or critically endangered in the IUCN Red List. Despite laying up to 100 eggs at a time, the survival rate is alarmingly low, with only one hatchling typically reaching adulthood. In the wild, sea turtle hatchlings face numerous threats from predators such as sharks, bears, North American jaguars, foxes, seabirds, and, of course, humans.

With a high mortality rate and long development periods, few hatchlings survive to maturity. Along the coastlines of Vietnam, sea turtle populations have been heavily impacted by human activities for decades. Turtles and their eggs are exploited for food, medicine, and for use in creating turtle shells, stuffed specimens, and ornaments. Furthermore, sea turtles are at risk from the loss of nesting sites due to coastal development, such as land reclamation and construction. They also become entangled in fishing nets, or ingest plastic and debris, or collide with boats.

Climate change presents another significant threat, as the sex of sea turtle hatchlings is determined by the temperature of the sand where the eggs are buried.

Additionally, turtles are often victims of improper fishing practices, as many accidentally get caught in nets, unable to surface for air, ultimately leading to their death.

Turtles are often depicted in popular culture as calm, patient, and wise beings. Their long lifespan, slow movement, and tough shells make them symbols of longevity and stability across various global cultures.

Eastern Culture:

• The turtle serves as a symbol of stability, often linked to the highest deities. In both Tibet and India, the cosmic turtle is a manifestation of Bodhisattva or Vishnu, emerging from primordial waters and carrying the Earth on its back. The association with water signifies rebirth and the lunar cycle.
• In China, the turtle represents the North and Winter, often linked to the moon's phases.
• In Mongolian mythology, the golden turtle supports the central mountain of the universe.
• The Kamouk people believe that the cosmic turtle will feel the heat of the sun and, in response, will roll over, thus causing the apocalypse.

Vietnamese Culture:

• In Vietnamese culture, the turtle is a sacred symbol, first appearing in the legend of King An Dương Vương during the founding of the Âu Lạc Kingdom. The divine Turtle, Kim Quy, appeared twice to aid the king. The first time, it helped the king build the Cổ Loa Citadel and provided a magical claw to create a divine crossbow, which could shoot thousands of arrows to protect the kingdom from foreign invaders. The second time, Kim Quy revealed the traitor Mỵ Châu and guided the king to the sea.
• The turtle also features prominently in the legend of Lê Lợi's struggle for independence. During the Ming invasion, the divine Turtle provided the hero Lê Lợi with a magical sword to defeat the invaders. Later, Kim Quy reclaimed the sword at Hoàn Kiếm Lake, which became known as the Lake of the Returned Sword.
• In Vietnam, the dragon and the turtle are both revered as sacred symbols of divine protection and the origin of the Vietnamese people.

Indigenous American Culture:

• The Maya depicted the Moon God wearing a shell armor.
• According to the Iroquois, the first woman fell from the sky to the sea, where a turtle saved her. The turtle's back became the first island, which eventually formed into Earth.
• In Algonquin mythology, the Great Turtle reappears twice to ensure the survival of humanity. First, it appears as a young man with markings on his arms and legs, who miraculously impregnates the sky woman, leading to the birth of twin gods of good and evil. The second time, the good twin falls into a lake, where the Great Turtle guides him and gives him a bow and corn—one ripe for planting and one immature for roasting.
• These beliefs are found among various Native American tribes, including the Sioux and the Huron.

Currently, both global and Vietnamese sea turtle populations are facing significant declines. All five sea turtle species found in Vietnam are listed in the 2007 Vietnam Red Book.

The leatherback turtle, once common in Vietnam's coastal waters over 30 years ago, had an annual nesting count of approximately 500 individuals. However, in recent years, only about 1-2 turtles nest annually along the central coast, with few to none in other regions.

The hawksbill turtle was once found in abundance in areas like Bai Tu Long Bay and central Vietnam. Today, only about 10 turtles return to nest each year at beaches in Bai Tu Long, Son Tra Peninsula, and Quang Binh province.

The green turtle is the most common species in Vietnamese waters. In the 1970s, it was estimated that around:

• 100 turtles nested in the islands of the Gulf of Tonkin
• 500 nested along the coastal islands of Central Vietnam
• 230 nested in Con Dao and 100 in the islands of the Gulf of Thailand

However, recent surveys show a sharp decline in green turtle populations across all regions. Aside from Con Dao, where nesting populations remain relatively stable, other areas now report only a few turtles each year.

In reality, sea turtles face constant threats that contribute to their declining populations. Turtles' nests are often raided, and hatchlings are preyed upon by various predators. Additionally, turtles are vulnerable to diseases, including tumors.

Each of us can contribute to the protection of sea turtles:

• First, become an informed consumer. Never buy or sell turtle meat or turtle-derived souvenirs. All actions related to the exploitation, collection, buying, selling, or transportation of sea turtles and their products are illegal and subject to fines or criminal prosecution.
• Keep the marine environment clean and encourage others to do the same. Be cautious when fishing at sea, and regularly check fishing nets to rescue trapped turtles.
• Get involved in sea turtle conservation activities. Organizations like the International Union for Conservation of Nature (IUCN) hold annual programs, and you can register to participate!
• If you come across a sea turtle being captured, sold, or slaughtered, immediately report it to the relevant authorities or organizations such as the local Fisheries Department and IUCN for action.

The scientific name of sea turtles is Chelonioidea. If you didn't know, 'sea turtle' refers to a small group within the larger order of turtles, with a total of seven species of sea turtles worldwide. These creatures can be found in almost every ocean on Earth, except for the Arctic region.

Sea turtles are reptiles that closely resemble land turtles, freshwater turtles, and terrapins. Unlike their land counterparts, sea turtles cannot retract their head and limbs into their shells. Instead, they have four paddle-like flippers that help them navigate the waters.

The main diet of sea turtles includes sea grass, jellyfish, crabs, mollusks, and sponges. Most sea turtles inhabit tropical waters along the equator, except for the leatherback turtle, which can thrive in cooler temperate waters.

They are commonly found in seagrass beds, coral reefs, and coastal areas. Sea turtles often rest on the water's surface, in deep waters, or take shelter beneath rocks in shallow waters near the coast. Many divers have reported seeing sea turtles resting on coral reefs and rocky outcrops.

In a stable natural environment, sea turtles can enjoy a long life. Studies show that sea turtles can live for many years, with some individuals reaching 50 years or more—lifespan comparable to humans. Most sea turtle species take decades to reach maturity, typically between 20 and 30 years, and continue to reproduce for another 10 years. In fact, some sea turtles can live up to 80 years.

Sea turtles have roamed the oceans for over 110 million years. As a key species in marine ecosystems, including coral reefs and seagrass meadows, they also play an essential role by consuming large quantities of jellyfish, which helps maintain balance in their environments. Moreover, sea turtles contribute to local economies by attracting eco-tourism. Unfortunately, their populations are now in decline. Thousands of sea turtles are unintentionally caught in fishing nets each year, and the beaches they nest on are disappearing.

Currently, sea turtles are facing the threat of extinction due to environmental pollution and illegal poaching. All seven remaining species of sea turtles are listed on the IUCN Red List, despite their reputation as 'immortal' due to their remarkable longevity.

Sea turtles migrate hundreds, and sometimes even thousands, of kilometers, traveling from feeding areas to nesting sites and then returning. During nesting season, female turtles swim through the waves to the shore where they lay their eggs. They leave the water only for this purpose. The female digs a nest using her flippers and lays between 70 and 190 eggs. The eggs take 6-10 weeks to hatch, depending on environmental conditions.

The sex of the hatchlings is determined by the temperature of the sand where they are born:

• Below 30°C, the majority of hatchlings are male.
• Above 30°C, the majority are female.

Upon hatching, the baby turtles instinctively head toward the ocean, beginning a long journey ahead!

They live in deep waters until they are 5-10 years old. Once they grow to about 20 cm in size (the size of a small plate), they leave the deep water, returning to the coastal regions to live around coral reefs or seagrass beds.

Due to numerous threats, only 1 in every 1,000 to 10,000 hatchlings survive to adulthood.

Once mature, sea turtles begin the breeding process. Both males and females migrate back to the beaches where they were born to mate and lay eggs.

Their navigational abilities during migration, their ability to remember the location of their birthplace, and the reasons for female turtles choosing specific nesting sites remain a mystery that scientists have yet to fully uncover.